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ANNUAL REPORT FOR 2003
Pembroke Creek Mitigation Site
Chowan County
Project No. 8.T010602
TIP No. R-2512
Prepared By:
Office of Natural Environment & Roadside Environmental Unit
North Carolina Department of Transportation
December 2003 TABLE OF CONTENTS
SUMMARY...........................................................................................................1
1.0 INTRODUCTION.........................................................................................2
1.1 Project Description....................................................................................2
1.2 Purpose.....................................................................................................2
1.3 Project History...........................................................................................2
1.4 Debit Ledger.............................................................................................4
2.0 HYDROLOGY..............................................................................................4
2.1 Success Criteria........................................................................................5
2.2 Hydrologic Description..............................................................................5
2.3 Results of Hydrologic Monitoring..............................................................7
2.3.1 Site Data.............................................................................................7
2.3.2 Climatic Data.....................................................................................10
2.4 Conclusions……………………………………………………………………10
3.0 VEGETATION: PEMBROKE MITIGATION SITE.....................................12
3.1 Success Criteria......................................................................................12
3.2 Description of Species............................................................................12
3.3 Results of Vegetation Monitoring............................................................13
3.4 Conclusions............................................................................................13
4.0 OVERALL CONCLUSIONS/ RECOMMENDATIONS...............................14
TABLES
Table 1. Pembroke Creek Mitigation Site Debit Ledger.......................................4
Table 2. Hydrologic Monitoring Results...............................................................7
Table 3. Hydrologic Monitoring Results (1999- 2002)..........................................8
Table 4. Vegetation Monitoring Results.............................................................13
FIGURES
Figure 1. Site Location Map.................................................................................3
Figure 2. Monitoring Gauge Locations.................................................................6
Figure 3. Hydrologic Monitoring Gauge Results...................................................9
Figure 4. Historical Rainfall Data (30-70 Graph)................................................11
APPENDICES
Appendix A. Gauge Data Graphs.......................................................................15
Appendix B. Site Photos....................................................................................16
SUMMARY
The following report summarizes the monitoring activities that have occurred in the past year at the Pembroke Creek Mitigation Site. The Pembroke Creek Mitigation Site in Chowan County is a bottomland forest site that is divided into two areas. The site was constructed to mitigate for the wetland impacts from the improvements to US 17 in Bertie and Chowan Counties (R-2512). In order to demonstrate successful mitigation, hydrologic and vegetative monitoring must be conducted for a minimum of five years or until the success criteria are fulfilled. Site construction began in 1998 and was finished in 1999.
Hydrologic success for this site is based on a comparison of mean depth of groundwater on the site to that reported from gauges in the monitored reference area (site data should fall within 20% of the reported reference data in a successful hydrologic year). The hydrologic results for 2003 indicated that the site met both jurisdictional success (i.e., the site was saturated within 12 inches of the surface for at least 12.5% of the growing season), as well as the modified criteria outlined in the plan.
The 2003-year represents the fifth successful year of vegetation monitoring. Vegetation monitoring indicated that the site has successful tree growth. The average survival over all three planting zones was 487 trees per acre. Each of the individual zones, as well as the overall site average, is above the requirement for year five (260 stems per acre).
Based on the results from the 2003 growing season and the past four successful years, NCDOT proposes to discontinue hydrology and vegetation monitoring on the Pembroke Creek Mitigation Site.
1
1.0 INTRODUCTION
1.1 Project Description
The site is located adjacent to US 17 in Chowan County (Figure 1). Designed as a bottomland forest, the site was constructed to mitigate for impacts from improvements to US 17 in Bertie and Chowan Counties (R-2512).
1.2 Purpose
In order to demonstrate successful mitigation, hydrologic and vegetative monitoring must be conducted for a minimum of five years. The following report details the results of hydrologic and vegetation monitoring during the 2003 growing season at the Pembroke Creek Mitigation Site. Included in this report are analyses of both hydrologic and vegetative monitoring results, as well as local climate conditions throughout the growing season.
1.3 Project History
November 1997 Site Constructed (Phase I)
January 1998 Site Planted (Phase I)
October 1998 Vegetation Monitoring (1 yr.) (Phase I)
November 1998 Site Constructed (Phase II)
February 1999 Monitoring Gauges Installed
March-December 1999 Hydrologic Monitoring (1 yr.)
March 1999 Site Planted (Phase II)
October 1999 Vegetation Monitoring (1 yr.)
March-December 2000 Hydrologic Monitoring (2 yr.)
August, October 2000 Vegetation Monitoring (2 yr.)
March-December 2001 Hydrologic Monitoring (3 yr.)
July 2001 Vegetation Monitoring (3 yr.)
March-December 2002 Hydrologic Monitoring (4 yr.)
September 2002 Vegetation Monitoring (4 yr.)
March-December 2003 Hydrologic Monitoring (5 yr.)
October 2003 Vegetation Monitoring (5 yr.)
2
Figure 1. Site Location Map
3
1.4 Debit Ledger
The Pembroke Creek Mitigation Site has provided mitigation for several highway projects. Table 1 shows the projects that this site is providing mitigation for since completion.
Table 1. Pembroke Creek Mitigation Site Debit Ledger
Pembroke Creek I
Mit. Plan
TIP DEBIT
TIP DEBIT
Chowan
Habitat
Acres
At Start:
Acres Remaining
R-2512A/Bmod
SPH Restoration
4.725
0
4.725
TOTAL
4.725
0
4.725
Pembroke Creek II
Mit. Plan
TIP DEBIT
TIP DEBIT
Chowan
Habitat
Acres
At Start:
Acres Remaining
R-2512 B mod
R-2404C
SPH Restoration
4.949
0
2.6
2.349
TOTAL
4.949
0
2.6
2.349 4
2.0 HYDROLOGY
2.1 Success Criteria
In accordance with federal guidelines for wetland mitigation, a site meets hydrologic criteria if it is inundated or saturated (within 12” of the surface) by surface or groundwater for at least 12.5% of the growing season (consecutive). However, discussions between NCDOT and natural resource agencies have determined that, due to the unique character of this site, the normal guidelines for hydrologic success may not apply. Groundwater levels may vary significantly on a daily basis due to a sandy substrate that is in close proximity to a tidally influenced body of water.
The growing season in Chowan County begins March 13 and ends December 1. These dates correspond to a 50% probability that air temperatures will drop to 28o or lower after March 13 and before December 1.1 Thus, the growing season is 262 days; optimal wetland hydrology requires saturation/inundation for 12.5% of this growing season, or 32 days. The site must also experience average climatic conditions in order for the hydrologic data to be considered valid.
2.2 Hydrologic Description
Eight groundwater-monitoring gauges (four site gauges, four reference gauges), one rain gauge, and one surface water gauge were installed onsite in February 1999; monitoring began in March 1999 (Figure 2). The automatic monitoring gauges and rain gauges record the depth to groundwater and rainfall, respectively. Data was collected on a daily basis throughout the growing season.
Appendix A contains a plot of the water depth for each monitoring gauge and surface water gauge in 2003. Precipitation events are included on each graph as bars.
1 Soil Conservation Service. Soil Survey of Chowan and Perquimans Counties, North Carolina, p.76.
5
Figure 2. Monitoring Gauge Locations 6
2.3 Results of Hydrologic Monitoring
2.3.1 Site Data
The maximum number of consecutive days that the groundwater was within twelve inches of the surface was determined for each gauge. The number of days was then converted into a percentage of the 262-day growing season. Table 2 and Figure 3 give the results for the 2003-growing season (March 13-December 1).
Table 2. Hydrologic Monitoring Results
Monitoring Gauge
< 5%
5% - 8%
8% - 12.5%
> 12.5%
Actual %
Dates of Success
PC-1+
r
78.2
March 14-Oct 4
Oct 28-Nov 30
PC-2+
r
63.4
March 14-Aug 26
Sept 1-Nov 30
PC-3+
r
100
March 14-Nov 30
PC-4+
r
100
March 14-Nov 30
PCR-1 *+
r
100
March 14-Nov 30
PCR-2 *+
r
100
March 14-Nov 30
PCR-3 *+
r
100
March 14-Nov 30
PCR-4 *+
r
100
March 14-Nov 30
* Reference gauge
+ Gauge met the success criterion during an average rainfall month (March, April, and November).
Standing water was observed throughout the growing season at the majority of the gauges.
7
Table 3. Hydrologic Monitoring Results (1999- 2002)
Monitoring Gauge
1999 %
Results
Pre Hurricane
1999 % Results
Post Hurricane
2000 % Results
2001 % Results
2002 % Results
PC-1
66
34
100
64
100
PC-2
23
34
21
18
25.2
PC-3
66
34
100
100
100
PC-4
66
34
100
100
100
PCR-1 *
66
34
100
100
100
PCR-2 *
51
34
100
100
100
PCR-3 *
66
34
100
100
100
PCR-4 *
66
34
100
100
100
Climate Conditions
Average Rainfall
Average Rainfall
Average Rainfall
Average to Below Average Rainfall
Average to Below Average Rainfall
* Reference gauge
Table 3 represents hydrologic data in percentages from previous years (1999-2002).
8
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2.3.2 Climatic Data
Figure 4 is a comparison of 2003 monthly rainfall to historical precipitation for the Edenton area. Rainfall data recorded onsite during the growing season was compared to the historical 30-70 percentile trends for the area. It is assumed that if the 2003 rainfall totals, represented by bars, fall between the average precipitation values for each month, then the local climate was experiencing average conditions for that particular region.
For the 2003-year, the only month to experience below average rainfall was June. The months of December (02’), January, March, April, and November all recorded average rainfall for the site. November (02’), February, May, July, August, September, and October experienced above average rainfall. The onsite rain gauge was used for the months of September-November 2003. Overall, 2003 experienced an average rainfall year.
2.4 Conclusions
The hydrologic monitoring results for the 2003-year indicate that the site is successful by jurisdictional standards. The mean saturation percentage of the onsite gauges (85.4%) fell within 20% of the mean for the four reference wetland gauges (100%). The 2003-year represents the fifth consecutive year for hydrology monitoring, therefore NCDOT proposes to discontinue hydrology monitoring on the Pembroke Creek Mitigation Site.
10
Figure 4. 30-70 Percentile Graph
Pembroke Creek 30-70 Percentile GraphEdenton, NC Monthly Rainfall02468101214Nov 02'Dec 02'Jan 03'Feb 03'Mar 03'Apr 03'MayJun 03'Jul 03'Aug 03'Sep 03'Oct 03'Nov 03'Dec 03'MonthPrecipitation (in.)2002 Rainfall2003 Rainfall30th Percentile70th Percentile70th Percentile30th PercentileOnsite rain gauge data was used for Sept-Nov 2003. 11
3.0 VEGETATION: PEMBROKE MITIGATION SITE
(YEAR 5 MONITORING)
3.1 Success Criteria
Success criteria state that there will be a minimum density of 320 trees per acre at year 3 and 260 trees per acre at year 5, of the approved target species surviving for at least three consecutive years.
3.2 Description of Species
The following tree species were planted in the Phase I Restoration Area:
Zone 1: (0.854 HA)
Chamaecyparis thyoides, Atlantic White Cedar Taxodium distichum, Baldcypress
Zone 2: (0.327 HA)
Nyssa aquatica, Tupelo Gum Fraxinus pennsylvanica, Green Ash Quercus lyrata, Overcup Oak
Taxodium distichum, Baldcypress
Zone 3: (0.468 HA)
Taxodium distichum, Baldcypress Nyssa aquatica, Tupelo Gum Nyssa sylvatica var. biflora, Swamp Blackgum
Fraxinus pennsylvanica, Green Ash
Phase II was planted in the winter of 1998-99. The following tree species were planted in the Phase II Restoration Area:
Zone 1: (0.88 HA)
Chamaecyparis thyoides, Atlantic White Cedar Taxodium distichum, Baldcypress
Zone 2: (0.35 HA)
Nyssa aquatica, Tupelo Gum Fraxinus pennsylvanica, Green Ash Quercus lyrata, Overcup Oak
Taxodium distichum, Baldcypress
Zone 3: (0.8 HA)
Taxodium distichum, Baldcypress Nyssa aquatica, Tupelo Gum Quercus lyrata, Overcup Oak
Fraxinus pennsylvanica, Green Ash
1 2
3.3 Results of Vegetation Monitoring
Table 4. Vegetation Monitoring Results ZO
ZO
ZO
NE 11204242858361321533309ZONE 1 AVERAGE DENSITY446NE 221864283063551131243037551ZONE 2 AVERAGE DENSITY593NE 33843153034042013713243506ZONE 3 AVERAGE DENSITY423TOTAL AVERAGE DENSITY487
Site Notes: Other species noted: cattail, woolgrass, arrowhead, phragmites, Eleocharis sp., Juncus effusus, red maple, sweetgum, black willow, Polygonum sp., briars, fennel, Baccharis sp., sycamore, jewelweed, pine, and smartweed.
3.4 Conclusions
The 2003 vegetation monitoring revealed an average density of 487 trees per acre. This average is well above the minimum of 260 trees per acre required by the success criteria.
NCDOT proposes to discontinue vegetation monitoring at the Pembroke Creek Mitigation Site.
1 3
4.0 OVERALL CONCLUSIONS/ RECOMMENDATIONS
The Pembroke Creek Mitigation Site was monitored for hydrology and vegetation for the fifth consecutive year in 2003. The hydrologic data indicates that the site has consistently met the success by jurisdictional standards, as well as those outlined in the mitigation plan. Vegetation monitoring for the site revealed that all three planting zones met the minimum requirement for tree survival, with the site having a 487 trees per acre overall surviving density.
Based upon the results of the fifth year of monitoring data, NCDOT proposes to discontinue hydrology and vegetation monitoring on the Pembroke Creek Mitigation Site.
1 4
APPENDIX A
GAUGE DATA GRAPHS
15 APPENDIX B
SITE PHOTOS & VEGETATION PLOTS
1 6
Pembroke
Photo 1 Photo 2
Photo 3 Photo 4
2003

ANNUAL REPORT FOR 2003
Pembroke Creek Mitigation Site
Chowan County
Project No. 8.T010602
TIP No. R-2512
Prepared By:
Office of Natural Environment & Roadside Environmental Unit
North Carolina Department of Transportation
December 2003 TABLE OF CONTENTS
SUMMARY...........................................................................................................1
1.0 INTRODUCTION.........................................................................................2
1.1 Project Description....................................................................................2
1.2 Purpose.....................................................................................................2
1.3 Project History...........................................................................................2
1.4 Debit Ledger.............................................................................................4
2.0 HYDROLOGY..............................................................................................4
2.1 Success Criteria........................................................................................5
2.2 Hydrologic Description..............................................................................5
2.3 Results of Hydrologic Monitoring..............................................................7
2.3.1 Site Data.............................................................................................7
2.3.2 Climatic Data.....................................................................................10
2.4 Conclusions……………………………………………………………………10
3.0 VEGETATION: PEMBROKE MITIGATION SITE.....................................12
3.1 Success Criteria......................................................................................12
3.2 Description of Species............................................................................12
3.3 Results of Vegetation Monitoring............................................................13
3.4 Conclusions............................................................................................13
4.0 OVERALL CONCLUSIONS/ RECOMMENDATIONS...............................14
TABLES
Table 1. Pembroke Creek Mitigation Site Debit Ledger.......................................4
Table 2. Hydrologic Monitoring Results...............................................................7
Table 3. Hydrologic Monitoring Results (1999- 2002)..........................................8
Table 4. Vegetation Monitoring Results.............................................................13
FIGURES
Figure 1. Site Location Map.................................................................................3
Figure 2. Monitoring Gauge Locations.................................................................6
Figure 3. Hydrologic Monitoring Gauge Results...................................................9
Figure 4. Historical Rainfall Data (30-70 Graph)................................................11
APPENDICES
Appendix A. Gauge Data Graphs.......................................................................15
Appendix B. Site Photos....................................................................................16
SUMMARY
The following report summarizes the monitoring activities that have occurred in the past year at the Pembroke Creek Mitigation Site. The Pembroke Creek Mitigation Site in Chowan County is a bottomland forest site that is divided into two areas. The site was constructed to mitigate for the wetland impacts from the improvements to US 17 in Bertie and Chowan Counties (R-2512). In order to demonstrate successful mitigation, hydrologic and vegetative monitoring must be conducted for a minimum of five years or until the success criteria are fulfilled. Site construction began in 1998 and was finished in 1999.
Hydrologic success for this site is based on a comparison of mean depth of groundwater on the site to that reported from gauges in the monitored reference area (site data should fall within 20% of the reported reference data in a successful hydrologic year). The hydrologic results for 2003 indicated that the site met both jurisdictional success (i.e., the site was saturated within 12 inches of the surface for at least 12.5% of the growing season), as well as the modified criteria outlined in the plan.
The 2003-year represents the fifth successful year of vegetation monitoring. Vegetation monitoring indicated that the site has successful tree growth. The average survival over all three planting zones was 487 trees per acre. Each of the individual zones, as well as the overall site average, is above the requirement for year five (260 stems per acre).
Based on the results from the 2003 growing season and the past four successful years, NCDOT proposes to discontinue hydrology and vegetation monitoring on the Pembroke Creek Mitigation Site.
1
1.0 INTRODUCTION
1.1 Project Description
The site is located adjacent to US 17 in Chowan County (Figure 1). Designed as a bottomland forest, the site was constructed to mitigate for impacts from improvements to US 17 in Bertie and Chowan Counties (R-2512).
1.2 Purpose
In order to demonstrate successful mitigation, hydrologic and vegetative monitoring must be conducted for a minimum of five years. The following report details the results of hydrologic and vegetation monitoring during the 2003 growing season at the Pembroke Creek Mitigation Site. Included in this report are analyses of both hydrologic and vegetative monitoring results, as well as local climate conditions throughout the growing season.
1.3 Project History
November 1997 Site Constructed (Phase I)
January 1998 Site Planted (Phase I)
October 1998 Vegetation Monitoring (1 yr.) (Phase I)
November 1998 Site Constructed (Phase II)
February 1999 Monitoring Gauges Installed
March-December 1999 Hydrologic Monitoring (1 yr.)
March 1999 Site Planted (Phase II)
October 1999 Vegetation Monitoring (1 yr.)
March-December 2000 Hydrologic Monitoring (2 yr.)
August, October 2000 Vegetation Monitoring (2 yr.)
March-December 2001 Hydrologic Monitoring (3 yr.)
July 2001 Vegetation Monitoring (3 yr.)
March-December 2002 Hydrologic Monitoring (4 yr.)
September 2002 Vegetation Monitoring (4 yr.)
March-December 2003 Hydrologic Monitoring (5 yr.)
October 2003 Vegetation Monitoring (5 yr.)
2
Figure 1. Site Location Map
3
1.4 Debit Ledger
The Pembroke Creek Mitigation Site has provided mitigation for several highway projects. Table 1 shows the projects that this site is providing mitigation for since completion.
Table 1. Pembroke Creek Mitigation Site Debit Ledger
Pembroke Creek I
Mit. Plan
TIP DEBIT
TIP DEBIT
Chowan
Habitat
Acres
At Start:
Acres Remaining
R-2512A/Bmod
SPH Restoration
4.725
0
4.725
TOTAL
4.725
0
4.725
Pembroke Creek II
Mit. Plan
TIP DEBIT
TIP DEBIT
Chowan
Habitat
Acres
At Start:
Acres Remaining
R-2512 B mod
R-2404C
SPH Restoration
4.949
0
2.6
2.349
TOTAL
4.949
0
2.6
2.349 4
2.0 HYDROLOGY
2.1 Success Criteria
In accordance with federal guidelines for wetland mitigation, a site meets hydrologic criteria if it is inundated or saturated (within 12” of the surface) by surface or groundwater for at least 12.5% of the growing season (consecutive). However, discussions between NCDOT and natural resource agencies have determined that, due to the unique character of this site, the normal guidelines for hydrologic success may not apply. Groundwater levels may vary significantly on a daily basis due to a sandy substrate that is in close proximity to a tidally influenced body of water.
The growing season in Chowan County begins March 13 and ends December 1. These dates correspond to a 50% probability that air temperatures will drop to 28o or lower after March 13 and before December 1.1 Thus, the growing season is 262 days; optimal wetland hydrology requires saturation/inundation for 12.5% of this growing season, or 32 days. The site must also experience average climatic conditions in order for the hydrologic data to be considered valid.
2.2 Hydrologic Description
Eight groundwater-monitoring gauges (four site gauges, four reference gauges), one rain gauge, and one surface water gauge were installed onsite in February 1999; monitoring began in March 1999 (Figure 2). The automatic monitoring gauges and rain gauges record the depth to groundwater and rainfall, respectively. Data was collected on a daily basis throughout the growing season.
Appendix A contains a plot of the water depth for each monitoring gauge and surface water gauge in 2003. Precipitation events are included on each graph as bars.
1 Soil Conservation Service. Soil Survey of Chowan and Perquimans Counties, North Carolina, p.76.
5
Figure 2. Monitoring Gauge Locations 6
2.3 Results of Hydrologic Monitoring
2.3.1 Site Data
The maximum number of consecutive days that the groundwater was within twelve inches of the surface was determined for each gauge. The number of days was then converted into a percentage of the 262-day growing season. Table 2 and Figure 3 give the results for the 2003-growing season (March 13-December 1).
Table 2. Hydrologic Monitoring Results
Monitoring Gauge
< 5%
5% - 8%
8% - 12.5%
> 12.5%
Actual %
Dates of Success
PC-1+
r
78.2
March 14-Oct 4
Oct 28-Nov 30
PC-2+
r
63.4
March 14-Aug 26
Sept 1-Nov 30
PC-3+
r
100
March 14-Nov 30
PC-4+
r
100
March 14-Nov 30
PCR-1 *+
r
100
March 14-Nov 30
PCR-2 *+
r
100
March 14-Nov 30
PCR-3 *+
r
100
March 14-Nov 30
PCR-4 *+
r
100
March 14-Nov 30
* Reference gauge
+ Gauge met the success criterion during an average rainfall month (March, April, and November).
Standing water was observed throughout the growing season at the majority of the gauges.
7
Table 3. Hydrologic Monitoring Results (1999- 2002)
Monitoring Gauge
1999 %
Results
Pre Hurricane
1999 % Results
Post Hurricane
2000 % Results
2001 % Results
2002 % Results
PC-1
66
34
100
64
100
PC-2
23
34
21
18
25.2
PC-3
66
34
100
100
100
PC-4
66
34
100
100
100
PCR-1 *
66
34
100
100
100
PCR-2 *
51
34
100
100
100
PCR-3 *
66
34
100
100
100
PCR-4 *
66
34
100
100
100
Climate Conditions
Average Rainfall
Average Rainfall
Average Rainfall
Average to Below Average Rainfall
Average to Below Average Rainfall
* Reference gauge
Table 3 represents hydrologic data in percentages from previous years (1999-2002).
8
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2.3.2 Climatic Data
Figure 4 is a comparison of 2003 monthly rainfall to historical precipitation for the Edenton area. Rainfall data recorded onsite during the growing season was compared to the historical 30-70 percentile trends for the area. It is assumed that if the 2003 rainfall totals, represented by bars, fall between the average precipitation values for each month, then the local climate was experiencing average conditions for that particular region.
For the 2003-year, the only month to experience below average rainfall was June. The months of December (02’), January, March, April, and November all recorded average rainfall for the site. November (02’), February, May, July, August, September, and October experienced above average rainfall. The onsite rain gauge was used for the months of September-November 2003. Overall, 2003 experienced an average rainfall year.
2.4 Conclusions
The hydrologic monitoring results for the 2003-year indicate that the site is successful by jurisdictional standards. The mean saturation percentage of the onsite gauges (85.4%) fell within 20% of the mean for the four reference wetland gauges (100%). The 2003-year represents the fifth consecutive year for hydrology monitoring, therefore NCDOT proposes to discontinue hydrology monitoring on the Pembroke Creek Mitigation Site.
10
Figure 4. 30-70 Percentile Graph
Pembroke Creek 30-70 Percentile GraphEdenton, NC Monthly Rainfall02468101214Nov 02'Dec 02'Jan 03'Feb 03'Mar 03'Apr 03'MayJun 03'Jul 03'Aug 03'Sep 03'Oct 03'Nov 03'Dec 03'MonthPrecipitation (in.)2002 Rainfall2003 Rainfall30th Percentile70th Percentile70th Percentile30th PercentileOnsite rain gauge data was used for Sept-Nov 2003. 11
3.0 VEGETATION: PEMBROKE MITIGATION SITE
(YEAR 5 MONITORING)
3.1 Success Criteria
Success criteria state that there will be a minimum density of 320 trees per acre at year 3 and 260 trees per acre at year 5, of the approved target species surviving for at least three consecutive years.
3.2 Description of Species
The following tree species were planted in the Phase I Restoration Area:
Zone 1: (0.854 HA)
Chamaecyparis thyoides, Atlantic White Cedar Taxodium distichum, Baldcypress
Zone 2: (0.327 HA)
Nyssa aquatica, Tupelo Gum Fraxinus pennsylvanica, Green Ash Quercus lyrata, Overcup Oak
Taxodium distichum, Baldcypress
Zone 3: (0.468 HA)
Taxodium distichum, Baldcypress Nyssa aquatica, Tupelo Gum Nyssa sylvatica var. biflora, Swamp Blackgum
Fraxinus pennsylvanica, Green Ash
Phase II was planted in the winter of 1998-99. The following tree species were planted in the Phase II Restoration Area:
Zone 1: (0.88 HA)
Chamaecyparis thyoides, Atlantic White Cedar Taxodium distichum, Baldcypress
Zone 2: (0.35 HA)
Nyssa aquatica, Tupelo Gum Fraxinus pennsylvanica, Green Ash Quercus lyrata, Overcup Oak
Taxodium distichum, Baldcypress
Zone 3: (0.8 HA)
Taxodium distichum, Baldcypress Nyssa aquatica, Tupelo Gum Quercus lyrata, Overcup Oak
Fraxinus pennsylvanica, Green Ash
1 2
3.3 Results of Vegetation Monitoring
Table 4. Vegetation Monitoring Results ZO
ZO
ZO
NE 11204242858361321533309ZONE 1 AVERAGE DENSITY446NE 221864283063551131243037551ZONE 2 AVERAGE DENSITY593NE 33843153034042013713243506ZONE 3 AVERAGE DENSITY423TOTAL AVERAGE DENSITY487
Site Notes: Other species noted: cattail, woolgrass, arrowhead, phragmites, Eleocharis sp., Juncus effusus, red maple, sweetgum, black willow, Polygonum sp., briars, fennel, Baccharis sp., sycamore, jewelweed, pine, and smartweed.
3.4 Conclusions
The 2003 vegetation monitoring revealed an average density of 487 trees per acre. This average is well above the minimum of 260 trees per acre required by the success criteria.
NCDOT proposes to discontinue vegetation monitoring at the Pembroke Creek Mitigation Site.
1 3
4.0 OVERALL CONCLUSIONS/ RECOMMENDATIONS
The Pembroke Creek Mitigation Site was monitored for hydrology and vegetation for the fifth consecutive year in 2003. The hydrologic data indicates that the site has consistently met the success by jurisdictional standards, as well as those outlined in the mitigation plan. Vegetation monitoring for the site revealed that all three planting zones met the minimum requirement for tree survival, with the site having a 487 trees per acre overall surviving density.
Based upon the results of the fifth year of monitoring data, NCDOT proposes to discontinue hydrology and vegetation monitoring on the Pembroke Creek Mitigation Site.
1 4
APPENDIX A
GAUGE DATA GRAPHS
15 APPENDIX B
SITE PHOTOS & VEGETATION PLOTS
1 6
Pembroke
Photo 1 Photo 2
Photo 3 Photo 4
2003